New and Improved (I hope!)

<?php
    /**
     * Phoenix Hospitality Management System
     * Phoenix REST API - API Department Repository file
     * Written in PHP using the Slim micro-framework
     *
     * @author Troy L. Marker
     * @version 1.0.0
     * @since 0.5.0
     * @copyright Copyright (c) 2020-2021 By Troy Marker Enterprises
     *
     * Declare name space and Import needed functions/classes
     */
    namespace App\Domain\Repository;

    use PDO;

    /**
     * This class provides a repository to the departments Database table
     */
    class Department {

        protected $connection;

        /**
         * Class constructor
         * @param PDO $connection - The database connection
         */
        public function __construct(PDO $connection) {
            $this->connection = $connection;
        }

        /**
         * This method inserts a new department into the database
         * @param array $Params - Method Parameters
         * @return array $AddRetval - Method Return value
         */
        public function add(array $params): string {
            $variables = ['department' => $params['department']];
            $statement = "SELECT id FROM " . strtolower($params['db']) . "_departments WHERE department=:department";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            if ($result->rowCount() > 0) {
                return false;
            }
            $statement = "INSERT INTO " . strtolower($params['db']) . "_departments SET department=:department;";
            $this->connection->prepare($statement)->execute($variables);
            return $params['department'];
        }

        /**
         * This method returns a list of departments
         * @param array $params - Method Parameters
         * @return array $ListsRetval - Method Return value
         */
        public function lists(array $params): array {
            if (isset($params['id'])) {
                $variables = ['id' => $params['id']];
                $statement = "SELECT department FROM " . strtolower($params['db']) . "_departments WHERE id=:id";
                $result = $this->connection->prepare($statement);
                $result->execute($variables);
                return $result->fetch(PDO::FETCH_ASSOC);
            }
            $statement = "SELECT * FROM " . strtolower($params['db']) . "_departments ORDER BY id";
            $result = $this->connection->prepare($statement);
            $result->execute();
            return $result->fetchAll(PDO::FETCH_ASSOC);
        }

        /**
         * This method will remove a department from the database
         * @param array $params - Method parameters
         * @return string $RemoveRetval - The name of the department removed.
         */
        public function remove(array $params): string {
            $variables = ['id' => $params['id']];
            $statement = "SELECT department FROM " . strtolower($params['db']) . "_departments WHERE id=:id";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            $return = $result->fetch(PDO::FETCH_ASSOC);
            $statement = "DELETE FROM " . strtolower($params['db']) . "_departments WHERE id=:id";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            return $return['department'];
        }


       /**
         * The method update all fields in a department record
         * @param array $params - Method parameters
         * @return array $ReplaceRetval - The method results
         */
        public function replace(array $params): array {
            $variables = ['id' => $params['id'], 'department' => $params['department']];
            $statement = "UPDATE " . strtolower($params['db']) . "_departments SET department=:department WHERE id=:id";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            return $this->lists($params);
        }

        /**
         * This method will change the name of a department in the database
         * @param array $params - Method parameters
         * @return array - Call success status with message
         */
        public function update(array $params): array {
            $variables = ['id' => $params['id'], 'department' => $params['department']];
            $statement = "UPDATE " . strtolower($params['db']) . "_departments SET department=:department WHERE id=:id";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            return $this->lists($params);
        }

        /**
         * This method will check if a department is in the database
         * @param array $params - Method parameters
         * @return boolean Method result
         */
        public function check(array $params): bool {
            $variables = ['department' => $params['department']];
            $statement = "SELECT * FROM " . strtolower($params['db']) . "_departments WHERE department=:department";
            $result = $this->connection->prepare($statement);
            $result->execute($variables);
            if ($result->rowCount() != 0) {
                return true;
            } else {
                return false;
            }
        }
    }